With development of the mobile Internet and popularization of an intelligent terminal, data traffic increases rapidly. A wireless local area network (WLAN) becomes one of mainstream mobile broadband access technologies due to advantages of a high rate and a low cost.
To greatly improve a service transmission rate of a WLAN system, a next-generation 802.11ax standard released by the Institute of Electrical and Electronics Engineers (IEEE) further uses an orthogonal frequency division multiple access (OFDMA) technology on a basis of an existing orthogonal frequency division multiplexing (OFDM) technology. With the OFDMA technology, an air interface wireless channel time-frequency resource is divided into multiple orthogonal time-frequency resource blocks (RB). RBs are sharable in time and orthogonal in a frequency domain.
The OFDMA technology supports multiple nodes to simultaneously send and receive data. When data needs to be transmitted between an access point and a station, resources are assigned based on an RB or an RB group; different channel resources are assigned to different STAs at the same time, so that multiple STAs are efficiently connected to a channel, and channel utilization is improved. For a WLAN system based on the OFDMA, a time-frequency resource needs to be efficiently indicated to the STA.